Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

Consider the region in the first quadrant of the xy-plane bounded by the graphs

ID: 2892162 • Letter: C

Question

Consider the region in the first quadrant of the xy-plane bounded by the graphs of y = 1 + Squareroot x, y = 2, and x = 9. The region is shaded in the graph below. (a) Set up integral to calculate the area of integrating with respect to y-(Do not integral.) (b) Set up an integral to the volume of the solid resulting from revolving this region around the line y = 1 using the disk/whaler method. (Do not evaluate the integral.) (c) Set up an integral to calculate the volume of the solid resulting from revolving this region around the line y = 1 using the shell method. (Do not evaluate the integral.)

Explanation / Answer

given curves y=1+x , y =2 , x=9

a)

y=1+x

=>x=y-1

=>x=(y-1)2

x=(y-1)2 , x=9

=>(y-1)2 =9

=> y-1 =3

=>y =4

2y4

area of the region = 24 [9-(y-1)2] dy

--------------------------------------------------------

b)

y=1+x , y =2

1+x =2

=>x =1

=>x =1

1x9

inner radius =2-(-1) =3

outer radius = (1+x)-(-1)=2+x

volume about y =-1 using washer method,V=19[(2+x)2-32] dx

-------------------------------------------------

c)x=(y-1)2 , x=9, 2y4

radius of shell =1+y

height of shell = 9-(y-1)2

volume about y =-1 using shell method,V=24 2(1+y)(9-(y-1)2) dy